/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

You can contact Cyan Worlds, Inc. by email legal@cyan.com
 or by snail mail at:
      Cyan Worlds, Inc.
      14617 N Newport Hwy
      Mead, WA   99021

*==LICENSE==*/
/*****************************************************************************
*
*   $/Plasma20/Sources/Plasma/NucleusLib/pnUtils/Private/Win32/pnUtW32Path.cpp
*   
***/

#include "../../Pch.h"
#pragma hdrstop


/*****************************************************************************
*
*   Local functions
*
***/

// make sure our definition is at least as big as the compiler's definition
COMPILER_ASSERT(MAX_PATH >= _MAX_PATH);


//===========================================================================
static inline bool IsSlash (wchar c) {
    return (c == L'\\') || (c == L'/');
}

//===========================================================================
static inline wchar ConvertSlash (wchar c) {
    return c != L'/' ? c : L'\\';
}

//===========================================================================
static inline bool IsUncPath (const wchar path[]) {
    return IsSlash(path[0]) && IsSlash(path[1]);
}

//===========================================================================
static const wchar * SkipUncDrive (const wchar path[]) {
    // UNC drive: "//server/share"

    // skip over leading "//"
    path += 2;

    // scan forward to end of server name
    for (;; ++path) {
        if (!*path)
            return path;
        if (IsSlash(*path))
            break;
    }

    // skip over '/'
    ++path;

    // skip over share name
    for (;; ++path) {
        if (!*path)
            return path;
        if (IsSlash(*path))
            return path;
    }
}

//===========================================================================
static wchar * PathSkipOverSeparator (wchar * path) {
    for (; *path; ++path) {
        if (IsSlash(*path))
            return path + 1;
    }

    return path;
}

//===========================================================================
static unsigned CommonPrefixLength (
    const wchar src1[],
    const wchar src2[]
) {
    ASSERT(src1);
    ASSERT(src2);

    wchar const * const base    = src1;
    const wchar * common        = nil;
    for (;;) {
        // Are the next components equal in length?
        const wchar * next1 = PathSkipOverSeparator(const_cast<wchar *>(src1));
        const wchar * next2 = PathSkipOverSeparator(const_cast<wchar *>(src2));
        const int componentLen = next1 - src1;
        if (componentLen != (next2 - src2))
            break;

        // Are the next components equal in value?
        if (!StrCmpI(src1, src2, componentLen))
            common = next1;
        else
            break;

        if (!*next1)
            break;
        src1 = next1 + 1;

        if (!*next2)
            break;
        src2 = next2 + 1;
    }

    if (!common)
        return 0;

    // Compute length of common subchunk;
    // if it is "C:" convert it to "C:\"
    unsigned commonLen = common - base;
    if ((commonLen == 2) && (base[1] == L':'))
        ++commonLen;
    return commonLen;
}

//===========================================================================
static void GetProgramName (
    void *      instance,
    wchar *     dst,
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(dstChars);

    if (!GetModuleFileNameW((HINSTANCE) instance, dst, dstChars)) {
        ErrorAssert(__LINE__, __FILE__, "GetModuleName failed");
        *dst = 0;
    }
}


/****************************************************************************
*
*   Exports
*
***/

//===========================================================================
void PathGetModuleName (
    wchar *     dst,
    unsigned    dstChars
) {
    GetProgramName(ModuleGetInstance(), dst, dstChars);
}

//===========================================================================
void PathGetProgramName (
    wchar *      dst,
    unsigned     dstChars
) {
    GetProgramName(nil, dst, dstChars);
}

//===========================================================================
bool PathFromString (
    wchar *      dst, 
    const wchar  src[], 
    unsigned     dstChars
) {
    ASSERT(dst);
    ASSERT(src);
    ASSERT(dstChars);

    for (;;) {
        // enable src and dst to be the same buffer
        wchar temp[MAX_PATH];
        if (dst == src) {
            StrCopy(temp, src, arrsize(temp));
            src = temp;
        }

        DWORD const result = GetFullPathNameW(src, dstChars, dst, 0);
        if (!result)
            break;
        if (dstChars < result)
            break;
        if (!dst[0])
            break;

        return true;
    }

    *dst = 0;
    return false;
}

//===========================================================================
bool PathFromString (
    wchar *     dst,                // ASSERT(dst);
    const wchar src[],              // ASSERT(src);
    unsigned    dstChars,           // ASSERT(dstChars);
    const wchar baseDir[]           // ASSERT(baseDir);
) {
    ASSERT(baseDir);
    ASSERT(dstChars);

    // Save current directory
    wchar curr[MAX_PATH];
    PathGetCurrentDirectory(curr, arrsize(curr));

    // Perform string conversion from specified directory
    bool result;
    if (0 != (result = PathSetCurrentDirectory(baseDir)))
        result = PathFromString(dst, src, dstChars);
    else
        *dst = 0;

    // Restore directory
    PathSetCurrentDirectory(curr);
    return result;
}

//===========================================================================
// this function was originally derived from _tsplitpath in the MSVCRT library,
// but has been updated to support UNC paths and to avoid blasting off the end
// of the buffers.
void PathSplitPath (
    const wchar     path[],
    wchar *         drive,
    wchar *         dir,
    wchar *         fname,
    wchar *         ext
) {
    ASSERT(path);
    ASSERT(path != drive);
    ASSERT(path != dir);
    ASSERT(path != fname);
    ASSERT(path != ext);

    // check for UNC path
    if (IsUncPath(path)) {
        const wchar * pathStart = path;
        path = SkipUncDrive(path);

        if (drive)
            StrCopy(drive, pathStart, min(MAX_DRIVE, path - pathStart + 1));
    }
    // regular DOS path
    else if (path[0] && (path[1] == L':')) {
        if (drive) {
            ASSERT(MAX_DRIVE >= 3);
            drive[0] = path[0];
            drive[1] = L':';
            drive[2] = L'\0';
        }

        path += 2; // skip over 'C' ':'
    }
    else if (drive) {
        *drive = 0;
    }

    // extract path string, if any.  Path now points to the first character
    // of the path, if any, or the filename or extension, if no path was
    // specified.  Scan ahead for the last occurence, if any, of a '/' or
    // '\' path separator character.  If none is found, there is no path.
    // We will also note the last '.' character found, if any, to aid in
    // handling the extension.
    const wchar *last_slash = nil, *last_dot = nil, *p = path;
    for (; *p; p++) {
        if (IsSlash(*p))
            last_slash = p + 1; // point to one beyond for later copy
        else if (*p == L'.')
            last_dot = p;
    }

    if (last_slash) {
        if (dir)
            StrCopy(dir, path, min(MAX_DIR, last_slash - path + 1));
        path = last_slash;
    }
    else if (dir) {
        *dir = 0;
    }

    // extract file name and extension, if any.  Path now points to the
    // first character of the file name, if any, or the extension if no
    // file name was given.  Dot points to the '.' beginning the extension,
    // if any.
    if (last_dot && (last_dot >= path)) {
        if (fname)
            StrCopy(fname, path, min(MAX_FNAME, last_dot - path + 1));
        if (ext)
            StrCopy(ext, last_dot, MAX_EXT);
    }
    else {
        if (fname)
            StrCopy(fname, path, MAX_FNAME);
        if (ext)
            *ext = 0;
    }
}

//===========================================================================
void PathMakePath (
    wchar *         path,
    unsigned        chars,
    const wchar     drive[],
    const wchar     dir[],
    const wchar     fname[],
    const wchar     ext[]
) {
    ASSERT(path);
    ASSERT(path != drive);
    ASSERT(path != dir);
    ASSERT(path != fname);
    ASSERT(path != ext);

    // save space for string terminator
    if (!chars--)
        return;

    // copy drive
    if (drive && *drive && chars) {
        do {
            *path++ = ConvertSlash(*drive++);
        } while (--chars && *drive);
        ASSERT(!IsSlash(path[-1]));
    }

    // copy directory
    if (dir && *dir && chars) {
        do {
            *path++ = ConvertSlash(*dir++);
        } while (--chars && *dir);

        // add trailing backslash
        if (chars && (path[-1] != '\\')) {
            *path++ = L'\\';
            chars--;
        }
    }

    // copy filename
    if (fname && *fname && chars) {
        // skip leading backslash
        if (IsSlash(*fname))
            ++fname;

        do {
            *path++ = ConvertSlash(*fname++);
        } while (--chars && *fname);
    }

    // copy extension
    if (ext && *ext && chars) {
        if (*ext != L'.') {
            *path++ = L'.';
            chars--;
        }
        while (chars-- && *ext)
            *path++ = ConvertSlash(*ext++);
    }

    // add string terminator
    *path = L'\0';
}

//===========================================================================
bool PathMakeRelative (
    wchar       *dst,
    unsigned    fromFlags,  // 0 or kPathFlagDirectory
    const wchar from[],
    unsigned    toFlags,    // 0 or kPathFlagDirectory
    const wchar to[],
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(from);
    ASSERT(to);
    ASSERT(dstChars);
    *dst = 0;

    unsigned prefixLength = CommonPrefixLength(from, to);
    if (!prefixLength)
        return false;

    wchar fromBuf[MAX_PATH];
    if (fromFlags & kPathFlagDirectory)
        StrCopy(fromBuf, from, arrsize(fromBuf));
    else
        PathRemoveFilename(fromBuf, from, arrsize(fromBuf));

    wchar toBuf[MAX_PATH];
    if (toFlags & kPathFlagDirectory)
        StrCopy(toBuf, to, arrsize(toBuf));
    else
        PathRemoveFilename(toBuf, to, arrsize(toBuf));

    const wchar * curr = fromBuf + prefixLength;
    if (*curr) {
        // build ..\.. part of the path
        if (IsSlash(*curr))
            curr++;              // skip slash

        while (*curr) {
            curr = PathSkipOverSeparator(const_cast<wchar *>(curr));
            StrPack(dst, *curr ? L"..\\" : L"..", dstChars);
        }
    }
    else {
        StrCopy(dst, L".", dstChars);
    }

    if (to[prefixLength]) {
        // deal with root case
        if (!IsSlash(to[prefixLength]))
            --prefixLength;

        ASSERT(IsSlash(to[prefixLength]));
        StrPack(dst, to + prefixLength, dstChars);
    }

    return true;
}

//===========================================================================
bool PathIsRelative (
    const wchar src[]
) {
    ASSERT(src);
    if (!src[0])
        return true;
    if (IsSlash(src[0]))
        return false;
    if (src[1] == L':')
        return false;
    return true;
}

//===========================================================================
const wchar * PathFindFilename (
    const wchar path[]
) {
    ASSERT(path);

    if (IsUncPath(path))
        path = SkipUncDrive(path);

    const wchar * last_slash = path;
    for (const wchar * p = path; *p; p++) {
        if ((*p == L'/') || (*p == L'\\') || (*p == L':'))
            last_slash = p + 1;
    }

    return last_slash;
}

//===========================================================================
const wchar * PathFindExtension (
    const wchar path[]
) {
    ASSERT(path);

    const wchar * last_dot = 0;
    const wchar * p = PathFindFilename(path);
    for ( ; *p; p++) {
        if (*p == L'.')
            last_dot = p;
    }

    return last_dot ? last_dot : p;
}

//===========================================================================
void PathGetCurrentDirectory (
    wchar *     dst,
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(dstChars);

    DWORD result = GetCurrentDirectoryW(dstChars, dst);
    if (!result || (result >= dstChars)) {
        ErrorAssert(__LINE__, __FILE__, "GetDir failed");
        *dst = 0;
    }
}

//===========================================================================
void PathGetTempDirectory (
    wchar *     dst,
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(dstChars);

    DWORD result = GetTempPathW(dstChars, dst);
    if (!result || (result >= dstChars))
        StrCopy(dst, L"C:\\temp\\", dstChars);
}

//============================================================================
void PathGetUserDirectory (
    wchar *     dst,
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(dstChars);

    wchar temp[MAX_PATH]; // GetSpecialFolder path requires a buffer of MAX_PATH size or larger
    if (SHGetSpecialFolderPathW(NULL, temp, CSIDL_LOCAL_APPDATA, TRUE) == FALSE)
        StrCopy(temp, L"C:\\", arrsize(temp));

    // append the product name
    PathAddFilename(dst, temp, ProductLongName(), dstChars);

    // ensure it exists
    if (!PathDoesDirectoryExist(dst))
        PathCreateDirectory(dst, kPathCreateDirFlagEntireTree);
}

//============================================================================
void PathGetLogDirectory (
    wchar *     dst,
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(dstChars);
    PathGetUserDirectory(dst, dstChars);
    PathAddFilename(dst, dst, L"Log", dstChars);
    if (!PathDoesDirectoryExist(dst))
        PathCreateDirectory(dst, kPathCreateDirFlagEntireTree);
}

//============================================================================
void PathGetInitDirectory (
    wchar *     dst,
    unsigned    dstChars
) {
    ASSERT(dst);
    ASSERT(dstChars);
    PathGetUserDirectory(dst, dstChars);
    PathAddFilename(dst, dst, L"Init", dstChars);
    if (!PathDoesDirectoryExist(dst))
        PathCreateDirectory(dst, kPathCreateDirFlagEntireTree);
}

//===========================================================================
bool PathSetCurrentDirectory (
    const wchar path[]
) {
    ASSERT(path);
    return SetCurrentDirectoryW(path) != 0;
}

//===========================================================================
void PathSetProgramDirectory () {
    wchar dir[MAX_PATH];
    PathGetProgramDirectory(dir, arrsize(dir));
    PathSetCurrentDirectory(dir);
}

//===========================================================================
void PathFindFiles (
    ARRAY(PathFind) *   paths,
    const wchar         fileSpec[],
    unsigned            pathFlags
) {
    ASSERT(paths);
    ASSERT(fileSpec);

    HANDLE find;
    WIN32_FIND_DATAW fd;
    wchar directory[MAX_PATH];
    PathRemoveFilename(directory, fileSpec, arrsize(directory));
    if (INVALID_HANDLE_VALUE == (find = FindFirstFileW(fileSpec, &fd))) {
        DWORD err = GetLastError();
        if ((err != ERROR_FILE_NOT_FOUND) && (err != ERROR_PATH_NOT_FOUND))
            ASSERTMSG(err, "PathFindFiles failed");
    }
    else {
        // find all the items in the current directory
        do {
            unsigned fileFlags = 0;
            if (fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
                if (! (pathFlags & kPathFlagDirectory))
                    continue;

                // don't add "." and ".."
                if (fd.cFileName[0] == L'.') {
                    if (!fd.cFileName[1])
                        continue;
                    if (fd.cFileName[1] == L'.' && !fd.cFileName[2])
                        continue;
                }

                fileFlags = kPathFlagDirectory;
            }
            else {
                if (! (pathFlags & kPathFlagFile))
                    continue;
                fileFlags = kPathFlagFile;
            }
            if (fd.dwFileAttributes & FILE_ATTRIBUTE_HIDDEN) {
                if (! (pathFlags & kPathFlagHidden))
                    continue;
                fileFlags |= kPathFlagHidden;
            }
            if (fd.dwFileAttributes & FILE_ATTRIBUTE_SYSTEM) {
                if (! (pathFlags & kPathFlagSystem))
                    continue;
                fileFlags |= kPathFlagSystem;
            }

            // add this one to the list of found files
            PathFind * pf       = paths->New();
            pf->flags           = fileFlags;
            pf->fileLength      = ((qword) fd.nFileSizeHigh << 32) | fd.nFileSizeLow;
            pf->lastWriteTime   = * (const qword *) &fd.ftLastWriteTime;
            PathAddFilename(pf->name, directory, fd.cFileName, arrsize(pf->name));
        } while (FindNextFileW(find, &fd));
        FindClose(find);
    }

    // check for directory recursing
    if ((pathFlags & kPathFlagRecurse) || StrStr(fileSpec, L"**")) {
        // recurse directories
    }
    else {
        return;
    }

    wchar dirSpec[MAX_PATH];
    PathAddFilename(dirSpec, directory, L"*", arrsize(dirSpec));
    if (INVALID_HANDLE_VALUE == (find = FindFirstFileW(dirSpec, &fd))) {
        DWORD err = GetLastError();
        if ((err != ERROR_FILE_NOT_FOUND) && (err != ERROR_PATH_NOT_FOUND))
            ErrorAssert(__LINE__, __FILE__, "PathFindFiles failed");
        return;
    }

    // find all the directories in the current directory
    const wchar * spec = PathFindFilename(fileSpec);
    do {
        if (! (fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) {
            continue;
        }
        if (fd.dwFileAttributes & FILE_ATTRIBUTE_HIDDEN) {
            if (! (pathFlags & kPathFlagHidden))
                continue;
        }
        if (fd.dwFileAttributes & FILE_ATTRIBUTE_SYSTEM) {
            if (! (pathFlags & kPathFlagSystem))
                continue;
        }

        // don't recurse "." and ".."
        if (fd.cFileName[0] == L'.') {
            if (!fd.cFileName[1])
                continue;
            if (fd.cFileName[1] == L'.' && !fd.cFileName[2])
                continue;
        }

        // recursively search subdirectory
        PathAddFilename(dirSpec, directory, fd.cFileName, arrsize(dirSpec));
        PathAddFilename(dirSpec, dirSpec, spec, arrsize(dirSpec));
        PathFindFiles(paths, dirSpec, pathFlags);

    } while (FindNextFileW(find, &fd));
    FindClose(find);
}

//===========================================================================
EPathCreateDirError PathCreateDirectory (const wchar path[], unsigned flags) {
    ASSERT(path);

    // convert from relative path to full path
    wchar dir[MAX_PATH];
    if (!PathFromString(dir, path, arrsize(dir))) {
        return kPathCreateDirErrInvalidPath;
    }

    // are we going to build the entire directory tree?
    wchar * dirEnd;
    if (flags & kPathCreateDirFlagEntireTree) {
        dirEnd = dir;

        // skip over leading slashes in UNC paths
        while (IsSlash(*dirEnd))
            ++dirEnd;

        // skip forward to first directory
        dirEnd = PathSkipOverSeparator(dirEnd);
    }
    // we're only creating the very last entry in the path
    else {
        dirEnd = dir + StrLen(dir);
    }

    bool result = true;
    for (wchar saveChar = L' '; saveChar; *dirEnd++ = saveChar) {
        // find the end of the current directory string and terminate it
        dirEnd = PathSkipOverSeparator(dirEnd);
        saveChar = *dirEnd;
        *dirEnd = 0;

        // create the directory and track the result from the last call
        result = CreateDirectoryW(dir, (LPSECURITY_ATTRIBUTES) nil);
    }

    // if we successfully created the directory then we're done
    if (result) {
        // Avoid check for kPathCreateDirFlagOsError
        COMPILER_ASSERT(kPathCreateDirSuccess == NO_ERROR);
        return kPathCreateDirSuccess;
    }

    unsigned error = GetLastError();
    switch (error) {
        case ERROR_ACCESS_DENIED:
        return kPathCreateDirErrAccessDenied;

        case ERROR_ALREADY_EXISTS: {
            DWORD attrib;
            if (0xffffffff == (attrib = GetFileAttributesW(dir)))
                return kPathCreateDirErrInvalidPath;

            if (! (attrib & FILE_ATTRIBUTE_DIRECTORY))
                return kPathCreateDirErrFileWithSameName;

            if (flags & kPathCreateDirFlagCreateNew)
                return kPathCreateDirErrDirExists;
        }
        return kPathCreateDirSuccess;

        default:
        return kPathCreateDirErrInvalidPath;
    }
}

//===========================================================================
void PathDeleteDirectory (const wchar path[], unsigned flags) {
    ASSERT(path);

    // convert from relative path to full path
    wchar dir[MAX_PATH];
    if (!PathFromString(dir, path, arrsize(dir)))
        return;

    for (;;) {
        // Important: in order to ensure that we don't delete NTFS
        // partition links, we must ensure that this is a directory!
        dword attributes = GetFileAttributesW(dir);
        if (attributes == (dword) -1)
            break;
        if ((attributes & FILE_ATTRIBUTE_DIRECTORY) == 0)
            break;
        if (attributes & FILE_ATTRIBUTE_REPARSE_POINT)
            break;

        if (!RemoveDirectoryW(dir))
            break;

        if ((flags & kPathCreateDirFlagEntireTree) == 0)
            break;

        wchar * filename = PathFindFilename(dir);
        if (!filename)
            break;

        // Move up one level in the directory hierarchy
        unsigned oldLength = StrLen(dir);
        while ((filename > dir) && IsSlash(filename[-1]))
            --filename;
        *filename = 0;
        if (oldLength == StrLen(dir))
            break;
    }
}

//===========================================================================
bool PathDoesFileExist (const wchar fileName[]) {
    dword attributes = GetFileAttributesW(fileName);
    if (attributes == (dword) -1)
        return false;
    if (attributes & FILE_ATTRIBUTE_DIRECTORY)
        return false;
    return true;
}

//============================================================================
bool PathDoesDirectoryExist (const wchar directory[]) {
    dword attributes = GetFileAttributesW(directory);
    if (attributes == (dword) -1)
        return false;
    if (attributes & FILE_ATTRIBUTE_DIRECTORY)
        return true;
    return false;
}

//===========================================================================
bool PathDeleteFile (
    const wchar file[]
) {
    return DeleteFileW(file) != 0;
}

//===========================================================================
bool PathMoveFile (
    const wchar src[],
    const wchar dst[]
) {
    return MoveFileW(src, dst) != 0;
}

//===========================================================================
bool PathCopyFile (
    const wchar src[],
    const wchar dst[]
) {
    return CopyFileW(src, dst, FALSE) != 0;    
}